In hair ornament products such as a hairpiece, a hair wig, crepe hair, a hair band, and doll hair, human hair has been conventionally used. However, in recent years, it is becoming difficult to obtain human hair, and the importance of fibers for artificial hair, instead of human hair, is increasing. As a fiber material for artificial hair, modacrylic fibers have been used in most cases, taking advantage of the feature of flame retardance; however, the modacrylic fibers do not have sufficient heat resistance. Then, it has been proposed that polyester-based fibers excellent in heat resistance be used as fibers for artificial hair. However, the polyester-based fibers are usually spun by melt spinning, and hence have a very smooth fiber surface and peculiar mirror-surface gloss although having sufficient heat resistance. Therefore, when the polyester-based fibers are used for hair ornament products to be attached to human hair, such as a hair wig or a hairpiece, a feeling of wrongness is caused.
Then, various methods for ameliorating gloss of the polyester-based fibers have been studied. For example, Patent Document 1 proposes that a brominated epoxy flame retardant and organic fine particles and/or inorganic fine particles be added to a polyester resin. Patent Document 2 proposes that brominated epoxy flame retardant having a number-average molecular weight of 20,000 or more be added to a polyester resin. Patent Document 3 proposes that a brominated epoxy flame retardant and a reaction accelerator be added to a polyester resin. Patent Document 4 proposes that a brominated epoxy flame retardant and an ester interchange suppressor be added to a polyester resin.